Geography

Tuesday, August 28, 2012

Air pollution in Singapore

AIR POLLUTION
One of the major pollutants in Singapore are sulphur dioxide (SO2). The sources of sulphur dioxide emissions in Singapore include power stations, refineries, other industries, shipping and other minor sources such as airport, vehicles and construction activities. The sulphur dioxide emission in 2010 inventory, which is developed based on extensive emissions data collected from various sources in 2007, is as shown:

Saturday, July 14, 2012

Some volcanic eruptions around the world

1. Mt. Tambora, IndonesiaDeath Toll: 92,000

The eruption of Tambora killed an estimated 92,000 people, including 10,000 from explosion and ash fall, and 82,000 from other related causes.
The concussion from the explosion was felt as far as a thousand miles away. Mt. Tambora, which was more than 13,000 feet tall before the explosion was reduced to 9,000 feet after ejecting more than 93 cubic miles of debris into the atmosphere.
The effects of the eruption were felt worldwide: 1816 became known as the “year without a summer” because of the volcanic ash in the atmosphere that lowered worldwide temperatures. It snowed in New England that June, and crop failures were common throughout Northern Europe and North America. As many as 100,000 additional deaths from starvation in these areas are thought to be traced to the eruption.

2. Mt. Pelee, West IndiesDeath Toll: 40,000

Thought to be dormant, Mt. Pelee began a series of eruptions on April 25, 1902. The primary eruption, on May 8 completely destroyed the city of St. Pierre, killing 25,000. The only survivors were a man held in a prison cell, and a man who lived on the outskirts of the town. Several ships were also destroyed.

3. Mt. Krakatoa, IndonesiaDeath Toll: 36,000

The August 1883 of Mt. Krakatoa (Krakatua) destroyed 2/3 of the island, ejecting more than six cubic miles of debris into the atmosphere. The sound of the explosion was the loudest ever documented, and was heard as far away as Australia.
Interestingly, it’s probable that no one died in the initial explosion. The casualties all came from the resulting tsunami.

4. Mt. Vesuvius, ItalyDeath Toll: 10,000+

In one of the most famous eruptions of all time, Mt. Vesuvius erupted and completely destroyed the Roman towns of Pompeii and Herculaneum. The eruption, which is said to have lasted 19 hours, buried Pompeii in ten feet of volcanic ash. The intense heat—perhaps as much as 750 degrees—carbonized much of the organic material in the area. Many of the victims have been found with the tops of their heads missing—their brains having boiled and exploded.

Pollution in India

About 80 % of urban waste in India ends up in rivers where it destroys river ecosystems and make bodies of water unfit for human use. Untreated sewage often ends up in rivers and testing of the water from the Ganges River near Varanasi showed that levels of fecal coliform, a dangerous bacterium that comes from untreated sewage, were about 3,000 percent higher than what is considered safe for bathing. This is of course causing many illnesses. It also has to be said that India invested lots of money in clean-up efforts, especially in area of New Delhi, but is it not enough considering the fact that India is having a rapid growth of population. Worse of all, water-borne diseases in India are causing child mortality.

Air pollution is India is almost as much as in China and some experts believe that smog from India and China could even change weather patterns in North America. Even the famous Taj Mahal is becoming more and more yellow because of tremendous air pollution. India is already facing massive environmental damage and many deaths and diseases of human population are caused because of air and water pollution.

Indoor Air Pollution

Indoor air pollution is often more harmful than outdoor air pollution, because we spend more time indoor, in homes and offices. They can be much more polluted compared to outdoor air, and thus present a major health threat.

In order to reduce heating costs many people try to make their homes and offices more airtight which often leads to inadequate circulation of the air and high levels of indoor air pollution that could have adverse effects on human health. Indoor air pollution is particularly hazardous to elderly people and young children, and can not only lead to respiratory diseases like asthma but also cause heart problems.

Because we spend approximately 90% of our time indoors, the quality of indoor air is certainly one of the main prerequisites of the healthy life. We need to pay more attention on the quality of air we breathe in our homes and offices.

Indoor air pollution is yet to be widely recognized issue and there has been very little scientific data about emission rates from different appliances we use in our home and offices. There also hasn't been adequate regulation on indoor pollutants that would regulate the acceptable level of indoor air emissions.

Is Carbon Dioxide a pollutant?

In the last decade or so there have certainly been plenty of talks about carbon dioxide (CO2), particularly carbon dioxide emissions that are believed to be the main factor contributing to climate change and global warming impact. Does this make carbon dioxide a pollutant or not?

According to the U.S. environmental protection agency (EPA) carbon dioxide is a pollutant, together with other greenhouse gases primarily because of its role in contributing to climate change, and not because of any direct health effects.

CO2 is indeed an essential ingredient of all life on our planet, a gas that humans exhale and plants inhale, the gas of vital importance for one of the most important processes on Earth- photosynthesis.

Carbon dioxide is thought by many scientists to be the greenhouse gas mostly responsible for climate change. The more CO2 in the atmosphere, the more heat gets trapped, leading to climate change and global temperature increase. This means that carbon dioxide can even be considered as the main pollutant that is warming our planet, opening door for the future environmental disaster of enormous proportions.

Thermal Pollution

Thermal pollution is a form of water pollution characterized by the degradation of water quality due to the rise or fall in the temperature of certain water body and is almost always caused by humans, and is mostly the result of use of water as a coolant in power plants and different industrial facilities.

It can lead to increased levels of chemical pollution because toxicity of many harmful chemicals often increases with the increase in temperature.

Thermal water pollution can cause huge damage to many aquatic ecosystems because there are many fish and other aquatic organisms that have adapted to particular temperature of the water and once this temperature changes they often fail to adapt and die in the process as a result of thermal shock.

The higher water temperatures can also lead to increased bacteria levels and reduced biodiversity of the affected aream causing migration of many fish species.

Thermal water pollutin can also be caused by the release of very cold water from the base of reservoirs and into warmer water bodies such as rivers. Even small temperature changes of one to two degrees Celsius can cause significant changes to many aquatic species and lead to loss in biodiversity.Howver, it can have beneficial effect and may even lead to positive impact on certain aquatic species such as manatee.

Threats to Singapore Reefs

Threats to Singapore Reefs

There were once over 60 offshore islands and patch reefs around Singapore, most of which were situtated south of mainland Singapore. However, since the 1970s, major land reclamation were carried out on the mainland and offshore Southern islands, adding to Singapore total land area. However, the most significant cause of reef degradation in Singapore is sedimentation. Land reclamation (occured along the Southwest Coast of the mainland and on some of the offshore Southern islands), dredging of shipping channels and dumping of earth spoils have increased the sediment load. Increased sedimentation can affect the reefs by causing a a slow but steady reduction in live coral cover (surveys since 1986 indicated decrease by up to 20% on some reefs), and by reducing the lower depth limit of coral growth on reef slopes (due to reduction in sunlight penetration). In the 1970s, coral growth extended to 10m down the reef slopes but today, growth is restricted to 6-8m.

Accidental oil spills also remains as an ever-present threat. Though the 1997 Evoikos oil spills (27,000 tonnes) did not seriously affect coral reefs, it contaminated the upper part of some reef flats.

Recreational and tourism-related use also have impacts on the reefs. For example, anchor damge cause by fishing boats and pleasure craft and negligent/inexperienced divers with proper bouyancy control, which can severly damage fragile, slow-growing corals.

The 1998 coral bleaching event

Sea temperature around Pulau Hantu and St John's were elevated by 1-2degree celsius from March-June 1998. 50-90% of all reef organisms in Singapore was affected, particularly the hard corals, soft corals and anemones. The bleaching effect extended until 6m, the lower growth depth limit for coral growth locally.